Anyone who has suffered the very unpleasant experience that is food poisoning will be happy to hear that researchers have developed technology enabling the high-speed detection of the toxic proteins that cause it. The new sensor was manufactured by employing a combination of artificial antibodies which capture these toxic proteins and a signal converter which converts those “capturing events” into optical signals.

The sensor developed by researchers at Fujitsu Laboratories Ltd. and Nagoya University, can detect toxic proteins 100 times faster than previous methods and is designed to enable faster and more accurate inspections of shipments of highly perishable foods such as dairy products.

The detection of toxic proteins requires specific antibodies to be employed, however, conventional antibodies require the use of a mammalian immune system in order to be developed. This is costly and is not conducive to maintaining a fixed level of quality. Also, conventional measuring technologies do not feature high accuracy when measuring minute quantities of toxic proteins, so they require bacteria to be cultured in order to increase the amount of toxic proteins, leading to a longer time required for measurement.

Artificial antibodies

To overcome these problems the researchers developed artificial antibody material that featured a strong affinity with proteins. This material was made by using DNA – which is stable and easy to handle – and side-chains resembling amino acids to modify the DNA. The artificial antibody material, which can be chemically synthesized in a short period of time, was then randomly connected, resulting in successful inexpensive creation of an artificial antibody library comprised of 1014 types of various multi-array artificial antibodies.

From within this vast library of artificial antibodies the researchers were able to select the artificial antibodies that feature strong affinity with toxic proteins, and also verified that the selected artificial antibodies can be applied to conventional biochemical testing methods.

Signal Converter

Once selected, the artificial antibodies were then attached to the tip of a signal converter, to which fluorescent dye was applied. When the proteins bond with these artificial antibodies, the fluorescence of the dye darkens. By observing fluctuations in the fluorescence of the dye, the presence of and amount of the targeted toxic proteins can be accurately measured.

To ensure that the sensor captures proteins efficiently, the researchers developed a technology that controls the flow of sample fluid that flows onto the sensor surface. This makes it possible for the sensor to rapidly capture approximately 90 percent of proteins present in the fluid.

Fujitsu says it plans to leverage the high protein-affinity and low cost accompanying these artificial-antibody technologies, so that some of the conventional antibodies used in food and disease testing can be replaced with artificial antibodies.